Such a light liquid separator is for instance known from EP 0 118 021 B1. According to this known separator the heavy liquid flows over the corresponding overflow wall into the heavy liquid outlet. A small flow opening is provided below the overflow edge of this overflow wall. This flow opening has the effect that the heavy liquid level drops further when the overflow edge of the overflow wall is reached and the flow of the inflowing mixture is stopped and, in the inoperative condition, adjusts itself at the level of the bottom of the flow opening. Upon corresponding inflow the heavy liquid level increases again so that the heavy liquid flows again over the overflow edge. Therefore, permanent heavy liquid level variations result which are utilized for the outflow of the light liquid.
If in the inoperative condition of the separator the heavy liquid level has reached its lowest level (bottom of the small flow opening), light liquid can still remain within the separator chamber which is removed only after a new inflow of mixture through the light liquid outlet.
Thus, a light-liquid separator which is especially effective with regard to the removal of light liquid from the separator chamber has not been provided yet.